Flexible microwave catheters for natural or artificial lumens

Abstract

A microwave delivery device, including a coaxial feedline having an inner conductor, an inner dielectric insulator coaxially disposed about the inner conductor, and an outer conductor coaxially disposed about the inner dielectric, and a radiating portion operably coupled to a distal end. The radiating portion includes a radiating portion inner conductor operable coupled to and extending from a distal end of the coaxial feedline inner conductor, a shielding outer conductor helically wrapped about the radiating portion inner conductor and operably coupled to the coaxial feedline outer conductor; and a shielding dielectric positioned between the radiating portion inner conductor and the shielding outer conductor wherein the width of the shielding outer conductor varies according to the longitudinal position thereof along the coaxial feedline inner conductor, and a cap operably coupled to a distal end of the radiating portion inner conductor and the shielding outer conductor to provide an electrical connection therebetween.

What is claimed is: 
     
       1. A flexible microwave catheter comprising:
 a catheter hub; 
 an outer sheath extending from the catheter hub, the outer sheath configured to prevent a release of microwave energy therethrough; and 
 a coaxial feedline disposed within the outer sheath, the coaxial feedline having an inner conductor, an inner dielectric coaxially disposed about the inner conductor, and an outer conductor coaxially disposed about the inner dielectric, wherein the coaxial feedline defines a radiating portion at a distal portion of the coaxial feedline, the radiating portion configured to emit microwave energy; and 
 wherein the coaxial feedline is slidable within the outer sheath and along a longitudinal axis of the outer sheath such that the radiating portion is selectively deployable from the outer sheath upon distal movement of the coaxial feedline relative to the outer sheath, and wherein the outer sheath includes a first inner diameter along at least a portion of the longitudinal axis and a distal portion of the outer sheath defines a sliding hub having a second inner diameter greater than the first inner diameter. 
 
     
     
       2. The flexible microwave catheter according to  claim 1 , wherein a width of the outer conductor of the radiating portion varies according to a longitudinal position thereof along the inner conductor of the radiating portion. 
     
     
       3. The flexible microwave catheter according to  claim 1 , further comprising a cap operably coupled to a distal end of the inner conductor and the outer conductor and providing an electrical connection therebetween. 
     
     
       4. The flexible microwave catheter according to  claim 1 , further comprising a temperature sensor disposed at a distal portion of the radiating portion. 
     
     
       5. The flexible microwave catheter according to  claim 1 , wherein a radiation pattern generated by the radiating portion is related to at least one of a variable width of the outer conductor or a variable helix angle of the outer conductor in the radiating portion. 
     
     
       6. The flexible microwave catheter according to  claim 1 , wherein the outer conductor in the radiating portion is helically wrapped about the inner conductor in the radiating portion, and wherein the radiating portion further includes a feed gap defined by a void formed between adjacent wraps of the outer conductor. 
     
     
       7. The flexible microwave catheter according to  claim 6 , wherein a feed gap ratio, defined by the ratio of a feed gap circumference and an outer conductor circumference along a cross section, changes linearly from a proximal end of the outer conductor in the radiating portion to a distal end of the outer conductor in the radiating portion. 
     
     
       8. The flexible microwave catheter according to  claim 7 , wherein the feed gap ratio varies between 0% at the proximal end of the radiating portion and about 50% at the distal end of the radiating portion. 
     
     
       9. The flexible microwave catheter according to  claim 1 , further comprising an actuator coupled to the coaxial feedline, the actuator configured to move the coaxial feedline relative to the catheter hub. 
     
     
       10. The flexible microwave catheter according to  claim 9 , wherein the actuator is configured to move the coaxial feedline relative to the outer sheath. 
     
     
       11. The flexible microwave catheter according to  claim 1 , wherein the radiating portion further comprises an outer dielectric insulating layer disposed about the outer conductor in the radiating portion, the outer dielectric insulating layer configured to slide along a length of the sliding hub and deploy from the sliding hub. 
     
     
       12. The flexible microwave catheter according to  claim 11 , wherein an outer surface of the outer dielectric insulating layer is movable along an inner surface of the sliding hub. 
     
     
       13. The flexible microwave catheter according to  claim 11 , wherein an outer diameter of the outer dielectric insulating layer is greater than the first inner diameter.